One type of logic gate is an XOR gate, which may also be called an exclusive OR gate. An XOR gate (or XOR circuit) acts in a same way as a logical “either/or.” That is, an output is HIGH (or logical “1”) if either, but not both, inputs are HIGH. The output is LOW (or logical “0”) if both inputs are LOW or if both inputs are HIGH. Stated differently, the output is HIGH if the inputs are different, but LOW if the inputs are the same.
XOR gates and other logic circuits have been provided in CML CMOS technology to enable high-speed circuit applications. CML logic may include current source devices, pull-up devices and pull-down devices. These applications may include, but are not limited to phase detectors of phase-locked-loops (PLLs) or delay-locked-loops (DLLs) and optical interconnects.